1. Field of the Invention
This invention relates generally to arrangements for welding tubular products, and more particularly, to a welding arrangement that will weld tubular products that require low cycle time, minimal misalignment, and near perfect radial alignment of the welded ends.
2. Description of the Related Art
To date many tubular products have been manufactured with the appropriate ends attached by conventional welding techniques. In the automotive industry, for example, particularly drive shaft manufacturing, the weld yokes, (or ends) often are pressed onto or into a tube end. After the press operation, the ends typically are welded by wire feed or other conventional welding techniques. The required press fit renders this method of manufacturing to be plagued with significant cost. It is of greater significance that only one end of the drive shaft is completed at a time. That is, after the completion of the first weld, the tube is turned over and reinserted into the known welding machine. Almost always the radial alignment and concentricity between the two ends is lost before the second weld yoke is attached. This form of manufacture, therefore, has significant inherent problems that are common in the industry. In addition, conventional wire feed welding imposes limits on the minimum wall thickness that can reliably be joined in production, and the quality of the weld cannot readily be ascertained.
In another known system, known magna pulse and magna arc methods are used in the construction of drive shafts and other tubular products. Again, typically one side of the tubular product is completed at a time. This causes set up problems that limit the ability to maintain radial alignment and verification of the quality of the weld is difficult to accomplish. Double ended magna arc or pulse welders are complex, difficult to repair and maintain, and expensive. In addition, They also require that extremely close tolerances be in squareness, cleanliness, and flatness of the components prior to and during the weld process to maintain a proper arc gap. This is difficult to accomplish and maintain in a production environment.
It is, therefore, an object of this invention to provide a system wherein the weld ends of a tubular assembly can be welded simultaneously in a simple, cost-effective and production robust manner.
It is also another object of this invention to provide a system wherein the weld ends of a tubular assembly can be maintained in a predetermined axial relationship as the ends are welded simultaneously.
It is another object of this invention to provide a welding arrangement that obviates the need for the press fit process and the associated close tolerance machining required for a press fit, as well as the additional material required on the yokes for the internal press fit.
It is also an object of this invention to provide a process that is cost effective, requires a short cycle time, holds near perfect concentricity of the tubular elements, and maintains near perfect radial alignment.
It is a further object of this invention to provide a welding system wherein a plurality of parameters that affect product quality can be recorded during the process to verify consistent weld quality.
It is additionally an object of this invention to provide an arrangement that can be applied in the welding of flat plate(s) to tubes or other forms of cylindrical stock.
It is yet a further object of this invention to provide a high level of precision and low cycle time in the manufacture of drive shafts, to preclude drive shafts that suffer from linear or radial misalignment in their welded ends, whereby high levels of noise, vibration and harshness (NVH) would result.